Continuity mistake: When Max is running out of the school after successfully becoming cool. We see his friend with the orange mohawk at least twice. Once hanging from a statue, and another where he's reaching out from a school bus. These two shots are really close together so there is no way that he could have moved that quick.
Continuity mistake: When Marie and Nutcracker are in Christmas Wood, some shooting stars fall to them and turn into sugar plums. In the first shot there are 3 of them, but when it cuts to the next shot where they turn into plums, suddenly there are 5. Then when the plums come down and begin circling around Nutcracker and Marie, there are 8 of them.
Continuity mistake: In the lunchroom when the boy gets tripped, a bunch of the food flies out of the bowl in the slow motion shot. When the bowl lands on Steve Guttenberg's head, it's full of food.
Continuity mistake: When Angus and Yellow reach the lake, Angus's face is tore up pretty bad, but after they cross the lake and go to the building on top of the mountain his face is almost completely free of any injuries.